1. Field of the Invention
The present general inventive concept relates to an audio system having a power amplifier, and more particularly, to a digital audio system to store and reproduce a digital pulse width modulation (PWM) signal and a processing method thereof.
2. Description of the Related Art
In general, a digital audio system uses a power amplifier as an audio device. The power amplifier is classified as class A, class B, class AB and class D amplifiers.
The class D amplifier can reduce amplification efficiency drops occurring in the class A, class B, and class AB amplifiers. The class D amplifier uses a method in which an audio signal is converted into pulse width modulation (PWM) signal and switched. Accordingly, the class D amplifier does not have a data conversion loss, and solves a nonlinear component occurring in the analog part starting from a switching circuit. Generally, an audio system using this power amplifier is composed of a microcomputer controlling the entire system, a digital signal processor processing a digital signal, a PWM unit generating a PWM signal by comparing an audio signal and a carrier signal, and a power amplifier amplifying the voltage and current of a PWM signal.
However, a conventional audio system using a power amplifier requires complicated hardware to generate a PWM signal in the system,
The power amplifier should be operated after a variety of signal processing operations, for example, pulse code modulation (PCM) data modulation, oversampling, neutral sampling, and noise sampling, are performed. In particular, if a portable device is designed to have a complicated hardware structure, the portable device consumes relatively more energy and the life of a battery is shortened.